1975-76 230 Models
Under certain conditions the switchover valve allows a small amount of exhaust gas back into the intake manifold. The EGR valve is controlled by engine temperature, engine speed, and the switchover valve. If oil temperature is below 77°F (25°C) or engine speed is above 3600 RPM, EGR does not take place. When oil temperature is above 77°F (25°C) and engine speed below 3600 RPM, switchover valve is energized and EGR takes place.